#pragma once

#include <iostream>
#include <queue>
#include <vector>
#include <pthread.h>
#include <functional>
#include "Log.hpp"
#include "Thread.hpp"
#include "LockGuard.hpp"

namespace ThreadNs
{
    static const int defaultnum = 8;

    class ThreadData
    {
    public:
        ThreadData(const std::string &name) : threadname(name)
        {
        }
        ~ThreadData()
        {
        }

    public:
        std::string threadname;
    };

    template <class T>
    class ThreadPool
    {
    private:
        ThreadPool(int thread_num = defaultnum) : _thread_num(thread_num)
        {
            pthread_mutex_init(&_mutex, nullptr);
            pthread_cond_init(&_cond, nullptr);
            // 构建指定个数的线程
            for (int i = 0; i < _thread_num; i++)
            {
                // 待优化
                std::string threadname = "thread-";
                threadname += std::to_string(i + 1);

                ThreadData td(threadname);

                // Thread<ThreadData> t(threadname,
                //                      std::bind(&ThreadPool<T>::ThreadRun, this, std::placeholders::_1), td);
                // _threads.push_back(t);
                _threads.emplace_back(threadname,
                                      std::bind(&ThreadPool<T>::ThreadRun, this,
                                                std::placeholders::_1),
                                      td);
                lg.LogMessage(Info, "%s is created...\n", threadname.c_str());
            }
        }
        ThreadPool(const ThreadPool<T> &tp) = delete;
        const ThreadPool<T> &operator=(const ThreadPool<T>) = delete;

    public:
        // 有线程安全问题的
        static ThreadPool<T> *GetInstance()
        {
            if (instance == nullptr)
            {
                LockGuard lockguard(&sig_lock);
                if (instance == nullptr)
                {
                    lg.LogMessage(Info, "创建单例成功...\n");
                    instance = new ThreadPool<T>();
                }
            }

            return instance;
        }
        bool Start()
        {
            // 启动
            for (auto &thread : _threads)
            {
                thread.Start();
                lg.LogMessage(Info, "%s is running ...\n", thread.ThreadName().c_str());
            }

            return true;
        }
        void ThreadWait(const ThreadData &td)
        {
            lg.LogMessage(Debug, "no task, %s is sleeping...\n", td.threadname.c_str());
            pthread_cond_wait(&_cond, &_mutex);
        }
        void ThreadWakeup()
        {
            pthread_cond_signal(&_cond);
        }
        void checkSelf()
        {
            // 1. _task_num > _task_num_high_water && _thread_num < _thread_num_high_water
            // 创建更多的线程，并且更新_thread_num

            // 2. _task_num == _task_num_low_water && _thread_num >= _thread_num_high_water
            // 把自己退出了，并且更新_thread_num
        }
        void ThreadRun(ThreadData &td)
        {
            while (true)
            {
                // checkSelf()
                // checkSelf();
                // 取任务
                T t;
                {
                    LockGuard lockguard(&_mutex);
                    while (_q.empty())
                    {
                        ThreadWait(td);
                        lg.LogMessage(Debug, "thread %s is wakeup\n", td.threadname.c_str());
                    }
                    t = _q.front();
                    _q.pop();
                }
                // 处理任务
                t();
                // lg.LogMessage(Debug, "%s handler task %s done, result is : %s\n",
                //               td.threadname, t.PrintTask().c_str(), t.PrintResult().c_str());
            }
        }
        void Push(T in)
        {
            LockGuard lockguard(&_mutex);
            _q.push(in);
            ThreadWakeup();
        }
        ~ThreadPool()
        {
            pthread_mutex_destroy(&_mutex);
            pthread_cond_destroy(&_cond);
        }

        // for debug
        void Wait()
        {
            for (auto &thread : _threads)
            {
                thread.Join();
            }
        }

    private:
        std::queue<T> _q;
        std::vector<Thread<ThreadData>> _threads;
        int _thread_num;
        pthread_mutex_t _mutex;
        pthread_cond_t _cond;

        static ThreadPool<T> *instance;
        static pthread_mutex_t sig_lock;
        // 扩展1：
        // int _thread_num;
        // int _task_num;

        // int _thread_num_low_water;  // 3
        // int _thread_num_high_water; // 10
        // int _task_num_low_water;    // 0
        // int _task_num_high_water;   // 30

        // 扩展2: 多进程+多线程

        // int number{1};
    };

    template <class T>
    ThreadPool<T> *ThreadPool<T>::instance = nullptr;
    template <class T>
    pthread_mutex_t ThreadPool<T>::sig_lock = PTHREAD_MUTEX_INITIALIZER;

}